<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: #cccccc;
        }
    </style>
    <script src="jquery-1.12.2.js"></script>
    <script>
        $(function () {
           $(document).keydown(function (e) {
               console.log(e.keyCode)
               var keyCode= e.keyCode
               switch (keyCode){
                   case 65:$("#dv").css("backgroundColor","red");
                       break;
                   case 66:$("#dv").css("backgroundColor","green");
                       break;
                   case 67:$("#dv").css("backgroundColor","blue");
                       break;
                   case 68:$("#dv").css("backgroundColor","yellow");
                       break;
                   case 69:$("#dv").css("backgroundColor","orange");
                       break;
                   case 70:$("#dv").css("backgroundColor","navy");
                       break;
                   case 71:$("#dv").css("backgroundColor","skyblue");
                       break;
                   case 13:$("#dv").css("borderRadius","50%");
                       break;
               }
           })
        })
    </script>
</head>
<body>
<div id="dv"></div>
</body>
</html>